Nevion AAV-HD-DMUX - Manual (Page 14)

AAV-HD-DMUX(-R)/ AAV-SD-DMUX(-R) Rev. 7
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3.3.3 RS422 Data port configuration
The RS422 data 8P8C Jack input must be configured with GYDA. The baud rate, data
length, parity and stop bits must be configured if UART mode is used.
The router destination where the data is to be embedded must be set up and the source
channel containing the received data that will be output on the 8P8C Jack must be also be
configured. See also Chapter 3.4 below.
3.3.4 Transport and shuffling of audio groups
The AAV-HD-DMUX stereo audio router involves de-embedding, buffering and re-embedding
which introduces a small delay relative to the video signal.
The group router is used to avoid this extra delay. Groups that only pass through the group
router are re-embedded in the same video line. This avoids any extra delay and means that
incompatible audio formats (asynchronous audio) may still be transported. The AAV-HD-
DMUX automatically uses the group router whenever possible when controlled with the DIP
switches.
“Shuffling” of groups is when existing embedded audio groups are re-assigned to different
groups. Copying of groups is also possible i.e. Group 1 may be transported to Group 1 and
duplicated to Group 2. This function also takes place in the group router which means that
there is no extra delay.
3.3.5 Audio generator
The stereo audio generator is available in the audio router as a source. It is a high purity 1
kHz sine wave with a 250ms interruption on the left channel every 3 seconds. The audio
level may be set to one of two standards. The two levels are -18 dBFS and -20 dBFS. These
two levels correspond to EBU R68 and SMPTE RP 155.
3.3.6 Video generator
The video generator has several different simple signals:

Color bar, 100% white, 75% colors, no set-up level.

Red, Green, Blue or Black full field.
The generator may be used as the video source if there is no video signal present at either of
the video inputs. The generator may also be switched on with GYDA. This will override video
input but the generator signal will be locked to the input.
The video standard of the generator may be set with GYDA but only if there is no video input
present.
3.3.7 Video input switching
The default mode of operation is auto-switch between the optical and electrical inputs. The
video output may be configured to either use the internal generator, or to switch off when no
video is detected on the inputs. The card will use the internal generator while it switches
between inputs until it finds a valid video signal.
There is also a manual input mode which disables the input automatic switching between
inputs. The video generator may be also selected to override the input video picture. The
input video will decide the timing of the output video and any embedded packets will still be
used by the module. Only the picture will be overwritten. If the video signal is removed
however, the input will not switch even if there is a valid signal at the other input.
3.3.8 De-glitching
Upstream video switching in a router causes glitches in the digital video. The module will
remove these glitches if the switch occurs on the correct video line for the standard in use.